1. Field of the Invention
The invention relates to a cryogenic pump with an essentially cup-shaped housing, with a radiation screen disposed in the housing and also essentially cup-shaped, with an inlet opening, with a cold head extending into the housing and the radiation screen, with pump surfaces for condensable gases, disposed on the cold head, with a collecting chamber for liquid condensate developing during regeneration of the pump and with an outlet pipe, which is used for removal of the gases which have settled on the pump surfaces during regeneration and the inlet opening of which is in the region of the collecting chamber.
2. Description of the Related Art
It had already been proposed in connection with a cryogenic pump of this type to achieve the regeneration of the pump surfaces --preferably the pump surfaces of the second stage of a two-stage cryogenic pump--in that the temperature of the pump surface to be regenerated and the pressure in the pump are raised to values above the triple point of the gases to be removed and that the condensates being removed from the pump surface are removed--in liquid and/or gas form--via the outlet pipe. The preferably liquid condensate being generated during the regeneration of the pump collects in the bottom region of the vertically attached pump and flows off to the outside through the outlet pipe, the inlet opening of which is located in the bottom region of the radiation screen. "Vertical attachment" is intended to mean that the axis of the pump which is essentially designed cup-shaped is essentially vertically disposed.
There is an increasing necessity to attach cryogenic pumps of the type described horizontally, i.e. they must be connected with a recipient in such a way that the axis of the pump housing extends horizontally. If the above described regeneration process is performed on a pump disposed in this manner, the liquid condensate no longer collects in the region of the inlet opening of the outlet pipe. A rapid removal of the condensate via the outlet pipe is therefore no longer possible, so that it becomes necessary to forego the advantage of the particularly short regeneration time of the described regenerating process. Because no clearly defined "lowest point" is present, only slowly evaporating condensate pools are formed. If this occurs in the region of the inlet flange, there is the danger of damage to the O-rings usually employed because of the cold acting on them, which results in leaks.
It is the object of the present invention to design a cryogenic pump with the characteristics of the preamble of claim 1 in such a way that the described disadvantages are no longer present.